So I walk in to a local cafe/roasterie today. I talk to the guy in charge of wholesale, tell him that I've got an espresso bar in the local growers and crafters markets, and let him know I'm always interested in trying new coffees. He gives me two bags to try. One organic blend and another organic single origin. Fabulous. I say I'd like to try a shot since the blend is what's in the grinder now. The barista grinds, tamps and pushes the buttons on the machine for a double and fills two shot glasses with an ounce and a half each. "18 seconds", he tells me, "perfect timing for a shot." I drink it. It's neither bad nor good. Somewhat balanced, but no mouthfeel or richness or body to the drink. A little watery I thought. Now this is the second barista (different coffee shop) I've had tell me that 18 seconds is perfect. Is this something that is taught in coffee shops? Just thought it was strange that it came up twice in different places.

as a general rule, the center of the bell curve in good coffee bars in the US tends to be extraction times between 22 and 28 seconds. obviously there are outliers on both ends, but they are outliers.